Speed reduction signal



July 28, 1931. c. T. MAGILL SPEEDv REDUCTION SIGNAL Filed'July 14, 1927 @wi/immo W JDM VCA Patented July 28, 1931 CHARLES T. MAG-ILL, OF OLARKDALE, ARIZONA SPEED REDUCTION SEGNAL Application filed July 14,

The invention relates to signalling means designed primarily for use on automobiles to give warning to following drivers that reduction in speed is to be made.

The principal object of my invention is to provide a speed reduction signal which is operatively connected with and controlled by pressure within a fluid circulating means of the machine on which the signal is used, said fluid circulating means being preferably the means for circulating lubricating oil for the motor.

In carrying out the above end, a further object is to provide a unique pressure-controlled means for in turn controlling the signal.

With the foregoing in view, the invention resides in the novel subject matter hereinafter described and claimed, the description being supplemented by the accompanying drawings.

Fig. 1 is a diagrammatic perspective view showing the signalling means operatively related with an automobile.

Fig. 2 is a vertical section through the pressure-controlled signal-controlling means.

Fig. 3 is an enlarged sectional view through the central parts shown in Fig. 2.

Fig. 4 is a horizontal section on line 4 4 of Fig. 3.

In the drawings above briefly described, the numeral 5 designates an automobile embodying the usual motor 6 having means for circula-ting lubricating oil, said means being shown as embodying an oil pump 7 provided with an inlet 8 from the sump of the motor and with an outlet 9 leading to the usual oil distributing means. Mounted upon the automobile 5, is a speed reduction signal 10 of any desired electrical nature. Appropriate wiring 11-12 and a cutout switch 13 are employed for the signal 10, and for controlling the circuit through the wiring, a pressurecontrolled switch means 14 is provided. Then this switch means and the switch 13 are closed, current from the usual automobile battery 15 illuminates or otherwise operates or attracts attention to the signal l0, but as long as the machine is driven at substantially a constant speed, or is increased from such 1927. Serial No. 205,675.

constant speed, t-he signal 10 does not come into play. Immediately however, upon reduction 1n speed from any at which the machine has been traveling, the switch 14. automatically acts to illuminate or otherwise operate he sigi'ial 10, giving warning to any vdrivers behind, that the speed of the machine is being checked. This operation of the switch 14 is made possible, due to the fact that this switch is subjected to the oil pressure supplied to the motor by the pump 7, unique provision being made whereby the switch is held open by such pressure at any speed of the machine, yet is permitted to close upon reduction of such speed.

The particular forni of switch herein disclosed, embodies two axially alined cylinders 16-17 having' a threaded connection 18 with each other at their inner ends, said inner end of the cylinder 16 being enlarged internally r to provide a space 19 within which certain contacts operate. A double-ended plunger 2O has its opposite ends mounted in the cylinders 16-17 respectively, and one or both ends of this plunger may be provided with packing rings such as 22. Cylinder 16 is provided with a pressure inlet 23 connected by a pipe or the like 24 with the discharge from the pump 7, so that the oil pressure within cylinder 16 and the oil circulating means of the machine, will be uniform and such pressurewill serve to force the plunger 2O toward the cylinder 17 to a greater or lesser extent, according to the speed of the motor 6. As plunger moves further into cylinder 1'?` it compresses air in the latter, the air pressure t'nus counterbalaneing the oil pressure and serving to hold the plunger 2O against morement as long as the motor is running at a uniform speed. As soon however as reduction in speed is made, the oil pressure proportionately reduces with the result that the air pressure in the cylinder 17, forces the plunger 2O further into the cylinder 16. These moyements of the plunger 20, effected by oil and air pressure, are relied upon to con trol the cir cuit of the signal 10.

Binding posts 25 are provided for the wiring 12, said posts passingl through .the enlarged inner end'of the cylinder 16 and being insulated therefrom. The inner ends of these binding posts carry contacts 26 of any path of a movable switch member 27 within the chamber 19, said switch member having Preferably, the switch member 27 is in the form of la metallic shell surrounding an insuand ring being split as at Q9 in Fig. Ll and being of self-contractmg nature to establish a lVhen the motor (i stands at rest, the switch member 27 engages the contacts 2G shown gnal 10 is then prevented from operating y switch 13. Upon starting the motor, the

pressure reaches the cylinder 16, it elevates the vplunger Q0, causing the ring 28 which switch member out of engagement with the contacts 2G, so that the signal 1() will not now creased, the plunger is forced further upward and during such movement, 1t merely ment of this ring and itsshell 27 being limited by the lower end of the cylinder 17. Thus,

chine be increased, the switch member 27 is held out of engagement with the contacts 2G immediately upon reduction 'of speed from that at which the machine has been operatder 17 by ascent of the plunger 20, comes into play to depress this plunger, such depression in the cylinder 16, incident to decrease lof motor speed. This descent of the fplunger 2O tacts 26, completing the circuit of the signal 10 and bringing the latter intol play, thus 1mdesired form. These contacts are in the a frictional connection with the plunger 20.

lating` ring 28 around the plunger, said shell frictional connection with said plunger.

in Figs. 2 and 3, but the vby opening the switch 13 is of course closed. As soon as oil controls 'the switch member 27 to elevate this be in operation. As the motor speed is inslides through the ring 28, the upward moveregardless of how much the speed of the maand the signal 10 will not operate. However,

ing, the compressed air trapped inthe cylinbeing permitted by reduction of oil pressure brings the switch member Q7 against the conmediately giving warning that the speed of the machine is being checked.

Preferably, the contacts 26 are spaced apart about one hundred and twenty degrees and a dead contact 26a is disposed between them. This arrangement prevents the con` tacts from having any tendency to cant the ring 28 on the plunger Q0 with danger of binding.

Excellent results are obtainable from the general construction shown and described and such construction is therefore preferably followed. However, it is to be understood that the present disclosure is illustrative rather than limiting in a numberof respects, and that within the scope of the invention as claimed, numerous variations may be made.

The particular switch shown in detail in Figs. 2, 3 and 4, is protected by my U. S. Patent 1,777,213 of September 30, 1930.

I claim 1. In an automobile, a motor, lubricating means for said motor having a pump driven by said motor, and a speed reduction warning signal for the drivers of following machines, and means controlled by the oil pressure out-put of said pump for operating said signal upon any decrease of motor speed, whereby any decrease of motor speed will operate said signal to give warning to the drivers of following machines.

2. ln `an automobile, a motor, lubricating means for said motor having a pump driven by said motor, said pump producing an oil pressure output which varies proportionately with motor speed, an electrical speed reduction warning signal for the drivers of following machines, a circuit for said signal embodying a switch, and means controlled by the oil pressure output of said .pump for holding said switch open during motor speed increase to any desired speed and during maintenance of said speed, and for automatically closing said switch upon any decrease of motor speed, whereby any decrease of motor speed will operate =said warning signal to give warning tothe drivers of following machines.

In testimony whereof I have hereunto affixed my signature.

CHARLES T. MAGILL. 

